Centrifugal pump



April 1l, 1961 T. McALPlNE 2,978,988

CENTRIFUGAL PUMP Filed Nov. l2, 1958 CENTRIFUGAL PUMP Thomas McAlpine, lCathcart, Glasgow, Scotland, `assignor t G. & J. Weir Limited, Cathcart, Glasgow, Scotland, a corporation of Great Britain and Northern Ireland Filed Nov. 12, 1958, Ser. No. 773,453

1 Claim. (Cl. 10S-.87)

This invention relates to improvements in centrifugal pumps.

A centrifugal pump according to the invention includes a driving motor attached to the pump casing cover, a pump impeller coupled to the motor, and a diffuser and a suction inlet guide also attached to the pump casing cover.

The pump impeller is carried by an extension of the motor shaft, or by a shaft which is coupled to the motor shaft.

According to a preferred construction the motor is mounted on top of a bracket which is an extension of the pump casing cover. The motor shaft is coupled to a pump shaft which carries the pump impeller. The diffuser is connected by a spacer to the pump casing cover. The impeller packing ring (or rings) is centered in an extension of the diffuser. The diifuser is centered on the spacer which in turn is centered on the pump casing cover, and the motor is centered in the cover bracket.

The central position of the impeller packing ring is, therefore, directly related to the motor and is independent of any error of alignment of the motor with the pump casing. The suction inlet guide is centered on an extension of the dituser to which it is attached. This guide has an ample clearance in relation to the pump casing.

A sealing plate associatedwith the inlet guide has a degree of exibility, allowing a sealing face thereon to press-contact the casing. Sealing is assisted by the discharge pressure of the pump acting on the sealing plate to press it against the pump casing.

A vertical-type centrifugal pump according to the invention is illustrated in the figure of the accompanying drawing which is a part elevation part axial section.

Referring to the drawings, the centrifugal pump shown includes a pump arranged on a Vertical axis and surmounted by a driving motor 11. The motor 11 is mounted on a bracket extension 12 of a pump casing cover 13 bolted to the pump casing l14. A pump impeller 15 is carried by a pump shaft 16 coupled to the motor shaft 17.

18 denotes a diffuser connected by a spacer 19' to the pump casing cover 13. An impeller packing ring 20 (or rings) is centered in an extension of the diffuser 18. The diffuser 18 is centered on the spacer 19 which 2,978,988 iatented Apr. 11, 1961 in turn is centered on the pump casing cover 13, and the motor 11 is centered in the cover bracket 12. Z1 denotes a suction inlet guide centered on and attached to the extension of the diffuser 18.

The central position of the impeller packing ring 20 is, therefore, directly related to the motor 11 and is independent of any error of alignment of the motor 11 with the pump casing 14. The suction inlet guide 21 has an ample clearance 22 in relation to the pump casing 14 at the suction inlet thereto, as shown.

A sealing plate 23 carried by the inlet guide 21 has a degree of liexibility, allowing a sealing face 24 thereon to press-contact the inside ofthe casing 14 around the suction inlet to the casing, sealing being assisted by the discharge pressure of the pump acting on the plate 23.

According to a modification, and as shown on the right-hand side of the axis of the pump, a sealing plate 23a is freely centered on the inlet guide 21 and cooperates with sealing faces 25, 26, respectively.

The construction is such that the pump assembly 15, 18, 19, 20, 2l may be lowered into the pump casing 14 Without risk of impairment of the relatively line clearances between the pump impeller 15 and the pump packing 20.

The driving motor 11 may consist of an electric motor as shown or, alternatively, it may consist of a steam turbine, or other source of motive power.

What is claimed is:

A centrifugal pump comprising a pump casing having a suction inlet, a cover iitted to said pump casing, a driving motor supported by said cover, an impeller located within said casing and operatively connected to said motor, a diffuser connected to said cover and surrounding the impeller, a suction inlet guide carried by said dilfuser and extending to the suction inlet in the casing, a flexible sealing plate on said inlet guide and engaged with said pump casing around the suction inlet, and impeller packing located adjacent said suction inlet guide between said diffuser and said impeller, said impeller, diffuser, impeller packing and suction inlet guide constituting an assembly the parts of which are all centered on said cover in relation to the axis of the impeller, so that said assembly may be lowered into said pump casing as a unit without risk of impairment of the relatively tine clearances -between said impeller and said impeller packmg.

References Cited in the file ofthis patent UNITED STATES PATENTS 2,434,979 Bergh Jan. 27, 1948 2,598,484 Adams May 27, 1952 2,799,227 Allen July 16, 1957 2,851,956 Lung Sept. 16, 1958 2,865,539 Edwards Dec. 23, 1958 2,887,061 Cametti et al. May 19, 1959 2,915,978 Schaefer Dec. 8, 1959 

